Expansion valve for rear seat air conditioner

ABSTRACT

The present invention relates to an expansion valve for a rear seat air conditioner of an automotive vehicle, which can circulate a flow of refrigerant stagnated between a compressor and the rear seat air conditioner through a bleeding channel of the expansion valve when only a front seat air conditioner is operated stopping the operation of the rear seat air conditioner, thereby supplying oil contained in refrigerant between the compressor and the rear seat air conditioner to the compressor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an expansion valve for a rear seat air conditioner of an automotive vehicle, and more particularly, to an expansion valve for a rear seat air conditioner of an automotive vehicle, which can circulate a flow of refrigerant stagnated between a compressor and the rear seat air conditioner through a bleeding channel of the expansion valve when only a front seat air conditioner is operated stopping operation of the rear seat air conditioner, thereby supplying oil contained in refrigerant between the compressor and the rear seat air conditioner to the compressor.

2. Background Art

In general, a rear seat air conditioner for a vehicle is applied to automotive vehicles of a large capacity, for instance, vans, RVs (Recreational Vehicles), or deluxe vehicles, as large as only a front seat air conditioner cannot agreeably cool or heat the inside of the vehicle. The rear seat air conditioner is installed in a sealed space of the rear of the vehicle in link with the front seat air conditioner, and so, constitutes a dual air conditioner together with the front seat air conditioner.

A dual air conditioner shown in FIG. 1 includes a front seat air conditioner 10 and a rear seat air conditioner 30.

The front seat air conditioner 10 includes: a compressor 12 for compressing and discharging refrigerant; a condenser 14 for condensing refrigerant discharged from the compressor 12; a receiver dryer 16 for separating gas from the condensed refrigerant; a front expansion valve 18 for expanding refrigerant discharged from the receiver dryer 16; a front evaporator 22 embedded in a front air conditioning case 20 for converting the air into cold air by thermally exchanging refrigerant supplied from the front expansion valve 18 and air blown from a front air blast 26 and sending refrigerant to the compressor 12; and a front heater core 24 embedded in the front air conditioning case 20 for converting the air into hot air by thermally exchanging cooling water flowing therein and air blown from the front air blast 26.

In addition, the rear seat air conditioner 30 includes: a rear expansion valve 34 for expanding refrigerant discharged from the receiver dryer 16 of the front seat air conditioner 10; a rear evaporator 36 embedded in a rear air conditioning case 32 for converting the air into cold air by thermally exchanging refrigerant supplied from the rear expansion valve 34 and air blown from a rear seat air blast 40 and sending refrigerant to the compressor 12; and a rear heater core 38 embedded in the rear air conditioning case 32 for converting the air into hot air by thermally exchanging cooling water flowing therein and air blown from the front air blast 40.

Meanwhile, the front expansion valve 18 or the rear expansion valve 34 is mounted on an inlet of the front evaporator 22 or the rear evaporator 36 and expands refrigerant of high temperature and high pressure discharged from the receiver dryer 16 to convert it into a low pressure state of a dew form and supply it to the evaporator, thereby increasing evaporation efficiency.

Since a thermal load of the air conditioner is changed by the outdoor temperature, humidity, the number of passengers, rotational frequency of the compressor 12, and so on, there is a need to adjust a flow rate of refrigerant circulating inside a cycle to show the best capability of each units coping with the change, and so, the expansion valves 18 and 34 serves to adjust the flow rate of refrigerant.

Moreover, if the thermal load is large in a state where the refrigerant amount is uniform, when refrigerant arrives at an outlet of the evaporator 22 or 36, since refrigerant is completely evaporated and absorbs heat more, temperature of refrigerant gas reaches an overheated state where it is higher than evaporation temperature. There is no problem if the overheated level is small, but if the overheated level is large, discharge temperature of the compressor 12 rises, and so, a cylinder (not shown) of the compressor 12 is heated. On the contrary, if the thermal load is small, refrigerant is not completely evaporated event at an outlet of the evaporator 22 or 36 and refrigerant of a liquid state is sucked into the compressor 12 to cause liquid compression, and thereby, a valve unit (not shown) of the compressor 12 is damaged. The expansion valves 18 and 34 serve to supply refrigerant of a proper amount to the evaporators 22 and 36 and to keep the overheated level in a fixed state even though there is a change in thermal load.

FIG. 2 shows an example of the rear expansion valve 34 of the expansion valves 18 and 34. The rear expansion valve 34 includes: a valve block 50; a low-pressure refrigerant channel 52 horizontally mounted on the upper end part of the valve block 50 for connecting the compressor 12 with the outlet of the rear evaporator 36; a high-pressure refrigerant channel 54 horizontally mounted on the lower end part of the valve block 50 and having an entrance portion 55 connected to the receiver dryer 16, a discharge portion 56 connected to the inlet of the rear evaporator 36, and an orifice 57 for connecting the entrance portion 55 and the discharge portion 56 with each other; a temperature sensing bulb 60 mounted on the upper end of the valve block 50; a pressure delivery bar 64 liftably mounted across the low-pressure refrigerant channel 52 and the orifice 57 of the high-pressure refrigerant channel 54 from the temperature sensing bulb 60; and a ball valve 68 mounted on a communication path 66 fluidically communicating with the orifice 57 and the entrance portion 55 to adjust an opening degree of the orifice 57 in link with the pressure delivery bar 64.

Operation of the rear expansion valve 34 will be described. When refrigerant is introduced from the receiver dryer 16 to the entrance portion 55 of the high-pressure refrigerant channel 54, the opening degree of the orifice 57 is adjusted according to ascent and descent of a ball 69 of the ball valve 68 due to a vertical movement of the pressure delivery bar 64. Therefore, refrigerant introduced into the entrance portion 55 can be supplied to the rear evaporator 36 through the communication path 66, the orifice 57 and the discharge portion 56 in order while adjusting its flow rate. That is, when temperature of refrigerant discharged from the rear evaporator 36 to the low-pressure refrigerant channel 52 is lowered, temperature of refrigerant is transferred to the temperature sensing bulb 60 through the pressure delivery bar 64. Therefore, temperature of a gas chamber 62 inside the temperature sensing bulb 60 is lowered, a diaphragm 61 mounted inside the temperature sensing bulb 60 is displaced upwardly, whereby the pressure delivery bar 64 is moved upwardly and the opening degree of the orifice 57 is reduced, so that the flow rate of refrigerant is reduced. On the contrary, when temperature of refrigerant flowing inside the low-pressure refrigerant channel 52 rises, the flow rate of refrigerant is increased.

However, in case of an automotive vehicle to which the dual air conditioner shown in FIG. 1 is applied, when there is no passenger on the rear seat, generally, only the front seat air conditioner 10 is operated stopping the operation of the rear seat air conditioner. In this instance, in the state where the prior art rear expansion valve 34 is applied, since the orifice 57 is intercepted, refrigerant circulation between the compressor 12 and the rear seat air conditioner 30 is stagnated. An oil content of refrigerant introduced into the compressor 12 may be indicated as an oil circulation rate. Since refrigerant circulation between the compressor 12 and the rear seat air conditioner 30 is stagnated, oil contained in refrigerant in the stagnated area cannot be supplied to the compressor 12. Therefore, as shown in FIG. 3, the oil circulation rate is reduced from the time when operation of the rear seat air conditioner 30 is stopped, and so, it may have a bad influence on durability of the compressor 12, for instance, sticking of the compressor 12, due to a lack of lubrication and cause a serious operational noise of the compressor 12 as operational time of the compressor 12 passes.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve the above problems occurring in the prior arts, and it is an object of the present invention to provide an expansion valve for a rear seat air conditioner of an automotive vehicle, which can circulate a flow of refrigerant stagnated between a compressor and the rear seat air conditioner through a bleeding channel of the expansion valve for the rear seat air conditioner when a front seat air conditioner is operated stopping the operation of the rear seat air conditioner, thereby supplying oil contained in refrigerant between the compressor and the rear seat air conditioner to the compressor.

To accomplish the above object, according to the present invention, there is provided an expansion valve for a rear seat air conditioner of an automotive vehicle including: a low-pressure refrigerant channel for connecting an outlet of a rear evaporator with a compressor; a high-pressure refrigerant channel having an entrance portion for introducing condensed refrigerant into the high-pressure refrigerant channel, a discharge portion connected to an inlet of the rear evaporator, and an orifice for connecting the entrance portion and the discharge portion with each other; a pressure delivery bar liftably mounted across the low-pressure refrigerant channel and the orifice of the high-pressure refrigerant channel; a temperature sensing bulb connected with the pressure delivery bar; and a ball valve mounted on a communication path fluidically communicating with the orifice and the entrance portion for adjusting an opening degree of the orifice in link with the pressure delivery bar, wherein the orifice includes a slant enlarged portion formed on the communication path side so that a ball of the ball valve is seated on the slant enlarged portion, and wherein the orifice has a bleeding channel formed on an inner circumferential surface thereof so as to fluidically communicate the communication path and the discharge portion with each other even when the ball of the ball valve is seated on the slant enlarged portion.

It is preferable that the bleeding channel includes a groove formed on the slant enlarged portion.

Moreover, it is preferable that the bleeding channel includes a groove or a concave formed on the ball side, which is in contact with the slant enlarged portion.

Furthermore, it is preferable that the orifice includes a straight portion formed on the discharge portion side, a diameter of the straight portion is within the range of 2.6 mm to 3.1 mm, and a diameter of the ball of the ball valve is within the range of 3.1 mm to 3.5 mm.

In addition, it is preferable that the bleeding channel has two to twelve grooves.

Additionally, it is preferable that a sectional area of the entire passageway of the grooves is corresponded to a sectional area of a circle, which has a diameter ranging 0.3 mm to 0.8 mm. The diameter is an equivalent diameter of the circle when a sectional area of the entire passageway of the grooves is converted into a circle.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention in conjunction with the accompanying drawings, in which:

FIG. 1 is a structural view showing an automotive vehicle to which a dual air conditioner is applied;

FIG. 2 is a sectional view of a prior art expansion valve for a prior art rear seat air conditioner;

FIG. 3 is a graph showing a change in an oil circulation rate by time when operation of the prior art rear seat air conditioner is stopped;

FIG. 4 is a sectional view of an expansion valve for a rear seat air conditioner according to the present invention;

FIG. 5 is a bottom enlarged view showing an example of an orifice of the expansion valve of FIG. 4;

FIG. 6 is a bottom enlarged view showing another example of the orifice of the expansion valve of FIG. 4;

FIG. 7 is a perspective view of a ball of a ball valve of the expansion valve according to the present invention; and

FIGS. 8 and 9 are graphs showing changes in an oil circulation rate by time when operation of the rear seat air conditioner to which the expansion valve of the present invention is applied is stopped.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will be now made in detail to the preferred embodiment of the present invention with reference to the attached drawings. Terms and words used in this specification and claims should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the inventor can properly define the concept of words to explain the inventor's invention in the best way.

FIG. 4 shows an expansion valve for a rear seat air conditioner of an automotive vehicle according to the present invention.

The expansion valve 100 for the rear seat air conditioner according to the present invention includes a valve block 110, a low-pressure refrigerant channel 120, a high-pressure refrigerant channel 130, a temperature sensing bulb 180, a pressure delivery bar 170, and a ball valve 160.

The low-pressure refrigerant channel 120 is horizontally mounted on the upper end part of the valve block 110 to connect an outlet of a rear evaporator 36 (see FIG. 1) constituting the rear seat air conditioner 30 (see FIG. 1) with a compressor 12 (see FIG. 1).

In addition, the high-pressure refrigerant channel 130 is horizontally mounted on the lower end part of the valve block 110 to connect an inlet of the rear evaporator 36 with a condenser 14 or a receiver dryer 16 (see FIG. 1). The high-pressure refrigerant channel 130 includes an entrance portion 132 connected with the condenser 14 or the receiver dryer 16 for introducing condensed refrigerant, a discharge portion 134 connected to the inlet of the rear evaporator 36, and an orifice 136 for connecting the entrance portion 132 and the discharge portion 134 with each other.

Moreover, the temperature sensing bulb 180 is mounted on the top of the valve block 110 and connected with the pressure delivery bar 170 liftably mounted across the low-pressure refrigerant channel 120 and the orifice 136 of the high-pressure refrigerant channel 130. In this instance, a diaphragm 182 mounted below a gas chamber 184 inside the temperature sensing bulb 180 is connected with the pressure delivery bar 170. Therefore, temperature of refrigerant flowing in the low-pressure refrigerant channel 120 is transferred to the gas chamber 184 through the pressure delivery bar 170, and so, the pressure delivery bar 170 is liftable while the diaphragm 182 is vertically moved according to a pressure change of the gas chamber 184.

The ball valve 160 is to adjust an opening degree of the orifice 136 in link with the pressure delivery bar 170, and mounted on a communication path 150 passing through the orifice 136 and the entrance portion 132. The ball valve 160 is arranged in close with the bottom of the lower end of the pressure delivery bar 170, and includes a ball 162 for adjusting the opening degree of the orifice 136 and a spring 164 for elastically supporting the ball 162 by interposing a support plate 166 between the ball 162 and the spring 164.

The expansion valve 100 for the rear seat air conditioner according to the present invention can circulate refrigerant between the rear seat air conditioner 30 and the compressor 12 even though the ball 162 of the ball valve 160 is seated on the orifice 136 in a state where only a front seat air conditioner 10 (see FIG. 1) is operated stopping the operation of the rear seat air conditioner 30 (see FIG. 1), whereby oil contained in refrigerant of the rear seat air conditioner 30 can be returned to the compressor 12 smoothly. To this end, a bleeding channel 140 is provided on the inner circumferential surface of the orifice 136 for fluidically communicating the communication path 150 and the discharge portion 134 with each other.

As shown in FIGS. 4 to 6, the bleeding channel 140 includes a number of grooves 142 formed on the inner peripheral surface of the orifice 136 to fluidically communicate the communication path 150 and the discharge portion 134 with each other.

In more concrete, the orifice 136 includes a straight portion 136 b of the discharge portion 134 side, and a slant enlarged portion 136 a of the communication path 150 side on which the ball 162 of the ball valve 160 is seated. In this instance, it is preferable that three or twelve grooves 142 are formed on the slant enlarged portion 136 a at predetermined intervals to fluidically communicate the communication path 150 with the straight portion 136 b even though the ball 162 of the ball valve 160 is seated on the slant enlarged portion 136 a. Therefore, even though the ball 162 of the ball valve 160 is seated on the slant enlarged portion 136 a, the communication path 150 can be fluidically communicated with the discharge portion 134 through the grooves 142 and the straight portion 136 b.

FIG. 5 shows an example that three grooves 142 are formed, and FIG. 6 shows another example that six grooves 142 are formed, but it is preferable that six grooves 142 are formed in consideration of flow-ability and process-ability of refrigerant. The grooves 142 can be formed, for example, by a notching method.

Furthermore, it is preferable that a diameter of the straight portion 136 b of the orifice is within the range of 2.6 mm to 3.1 mm and a diameter of the ball 162 of the ball valve 160 is within the range of 3.1 mm to 3.5 mm.

Additionally, it is preferable that a sectional area of the bleeding channel 140, namely, a sectional area of the entire passageway of the grooves 142 corresponds to a sectional area of a circle, which has a diameter of 0.3 mm to 0.8 mm.

Meanwhile, in this embodiment, the grooves 142 of the bleeding channel 140 are formed on the inner peripheral surface of the slant enlarged portion 136 a, but may be formed on the outer peripheral surface of the ball 162, which is in contact with the slant enlarged portion 136 a as shown in FIG. 7. In FIG. 7, the grooves 162 a are formed on the outer peripheral surface of the ball 162 in a lattice form, but may be formed in one of various shapes. In addition, not shown in the drawings, but the bleeding channel 140 may have a concave (not shown) formed on the outer peripheral surface of the ball 162.

Moreover, the ball 162 of the ball valve 160 may be formed in a spherical or conical shape or one of other shapes.

Next, the operation of the expansion valve for the rear seat air conditioner of the automotive vehicle according to the present invention will be described.

In case that the front and rear seat air conditioners 10 and 30 (see FIG. 1) constituting a dual air conditioner are all operated, when refrigerant is introduced from the receiver dryer 16 into the entrance portion 132 of the high-pressure refrigerant channel 130, the opening degree of the orifice 136 is adjusted according to rise and fall of the ball 162 of the ball valve 160 due to the vertical movement of the pressure delivery bar 170. Therefore, refrigerant introduced into the entrance portion 132 can be supplied to the rear evaporator 36 while controlling its flow rate after passing through the communication path 150, the orifice 136 and the discharge portion 134 in order.

A structure for adjusting the opening degree of the orifice 136 will be described in more detail. When temperature of refrigerant discharged from the rear evaporator 36 to the low-pressure refrigerant channel 120 drops, temperature of refrigerant is transferred to the temperature sensing bulb 180 through the pressure deliver bar 170. Therefore, temperature of the gas chamber 184 inside the temperature sensing bulb 180 drops and gas contained inside the gas chamber 184 is condensed, so that pressure of the gas chamber 184 is lowered and volume of the gas chamber 184 is reduced, whereby the diaphragm 182 mounted inside the temperature sensing bulb 180 is displaced upwardly. The pressure delivery bar 170 is moved upwardly in link with the displacement of the diaphragm 182 and the ball 162 of the ball valve 160 is moved upwardly by elasticity of the spring 164, whereby the opening degree of the orifice 136 is reduced and the flow rate of refrigerant is reduced. Contrariwise, when temperature of refrigerant flowing inside the low-pressure refrigerant channel 120 rises, the pressure delivery bar 170 moves downwardly and the opening degree of the orifice 136 is increased, whereby the flow rate of refrigerant is increased.

As described above, after the front and rear seat air conditioners 10 and 30 of the dual air conditioner are all operated, when only the front seat air conditioner 10 is operated stopping the operation of the rear seat air conditioner 30 in case that there is no passenger on the rear seat of the automotive vehicle, generally, the orifice 136 is intercepted and refrigerant cannot be circulated between the compressor 12 and the rear seat air conditioner 30 and is stagnated. Therefore, oil contained in refrigerant located in the stagnated area is not supplied to the compressor 12. However, in the present invention, refrigerant of a predetermined flow rate can be circulated between the compressor 12 and the rear seat air conditioner 30 through the bleeding channel 140 having the grooves 142 formed on the slant enlarged portion 136 a of the orifice 136.

That is, refrigerant of the entrance portion 132 can be flown to the discharge portion 134 after passing through the straight portion 136 b of the orifice 136 through the communication path 150 and the bleeding channel 140, whereby refrigerant of the predetermined flow rate can be circulated between the rear seat air conditioner 30 and the compressor 12 smoothly.

As described above, when refrigerant of the predetermined flow rate can be circulated between the rear seat air conditioner 30 and the compressor 12, oil contained in refrigerant in the area can be supplied to the compressor 12 smoothly so as to prevent a lack of lubrication of the compressor 12.

FIGS. 8 and 9 are graphs showing changes in an oil circulation rate by time when operation of the rear seat air conditioner to which the expansion valve of the present invention is applied is stopped. FIG. 8 shows a case that the diameter of the bleeding channel 140 is 0.3 mm, and FIG. 9 shows a case that the diameter of the bleeding channel 140 is 0.4 mm. As you can see from FIGS. 8 and 9, even though operation of the rear seat air conditioner 30 is stopped, oil is circulated through the bleeding channel 140, so that oil can be supplied to the compressor 12 smoothly and uniformly without reduction of the oil circulation rate as time goes.

The following Table 1 is to compare the oil circulation rate between the expansion valve according to the present invention and the prior art expansion valve to which the bleeding channel is not applied in case of a dual mode that the front and rear seat air conditioners are all operated and in case of a single mode that only the front seat air conditioner is operated stopping the operation of the rear seat air conditioner. For your reference, in Table 1, a dimension of the bleeding channel is indicated by converting a dimension corresponding to a sectional area of the entire passageway of the grooves 142 into a diameter of a circle. TABLE 1 Bleeding Operation Oil circulation rate (%) Division channel (mm) period (HR) Dual Single Prior art None 1 8.0 3.4 2 2.2 4 1.8 Present 0.6 1 8.2 8.8 invention 1 2 8.9 Present 0.5 1 8.0 7.8 invention 2 2 7.9 Present 0.4 1 8.4 7.7 invention 3 2 7.7 Present 0.3 1 8.3 6.7 invention 4 2 6.7

As indicated in the above Table 1, in the single mode, the oil circulation rate of the present invention was still higher than the prior art expansion valve, and did not drop even though time passed. In addition, not shown in Table 1, but even when refrigerant of the predetermined flow rate is circulated between the compressor and the rear seat air conditioner, cooling performance did not drop even though time passed.

As described above, the expansion valve for the rear seat air conditioner of the automotive vehicle according to the present invention can circulate refrigerant between the compressor and the rear seat air conditioner since refrigerant of the predetermined flow rate introduced into the entrance portion 132 from the receiver dryer can flow to the discharge portion 134, which is connected to the rear evaporator, through the bleeding channel 140 formed in the expansion valve even when operation of the rear seat air conditioner is stopped but only the front seat air conditioner is operated. Therefore, the present invention can smoothly supply oil contained in refrigerant between the compressor and the rear seat air conditioner to the compressor, thereby preventing bad influences on durability of the compressor, for example, sticking of the compressor due to a lack of lubrication as operation time of the compressor passes, and extending a lifespan of the compressor by protecting the compressor. In addition, the present invention can reduce operational noise of the compressor by raising a lubricating effect.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention. 

1. An expansion valve for a rear seat air conditioner of an automotive vehicle, which comprises: a low-pressure refrigerant channel for connecting an outlet of a rear evaporator with a compressor; a high-pressure refrigerant channel having an entrance portion for introducing refrigerant into the high-pressure refrigerant channel, a discharge portion connected to an inlet of the rear evaporator, and an orifice for connecting the entrance portion and the discharge portion with each other; a pressure delivery bar liftably mounted across the low-pressure refrigerant channel and the orifice of the high-pressure refrigerant channel; a temperature sensing bulb connected with the pressure delivery bar; and a ball valve mounted on a communication path fluidically communicating with the orifice and the entrance portion for adjusting an opening degree of the orifice in link with the pressure delivery bar, wherein the orifice includes a slant enlarged portion formed on the communication path side so that a ball of the ball valve is seated on the slant enlarged portion, and wherein the orifice has a bleeding channel formed on an inner circumferential surface thereof so as to fluidically communicate the communication path and the discharge portion with each other even when the ball of the ball valve is seated on the slant enlarged portion.
 2. The expansion valve according to claim 1, wherein the bleeding channel includes a groove formed on the slant enlarged portion.
 3. The expansion valve according to claim 1, wherein the bleeding channel includes a groove formed on the ball side, which is in contact with the slant enlarged portion.
 4. The expansion valve according to claim 1, wherein the orifice includes a straight portion formed on the discharge portion side, a diameter of the straight portion is within the range of 2.6 mm to 3.1 mm, and a diameter of the ball of the ball valve is within the range of 3.1 mm to 3.5 mm.
 5. The expansion valve according to claim 2, wherein the bleeding channel has three to twelve grooves.
 6. The expansion valve according to claim 2, wherein a sectional area of the entire passageway of the grooves is corresponded to a sectional area of a circle, which has a diameter ranging 0.3 mm to 0.8 mm. 